diff --git a/src/common/kernel/plane.c b/src/common/kernel/plane.c
index 84151b18b..be9b75db1 100644
--- a/src/common/kernel/plane.c
+++ b/src/common/kernel/plane.c
@@ -35,6 +35,8 @@
 #include <string.h>
 #include <stdlib.h>
 
+struct plane *planes;
+
 plane *
 getplane(const region *r)
 {
diff --git a/src/common/kernel/plane.h b/src/common/kernel/plane.h
index 229cd3211..ac0ef7635 100644
--- a/src/common/kernel/plane.h
+++ b/src/common/kernel/plane.h
@@ -57,12 +57,12 @@ typedef struct plane {
 	struct attrib *attribs;
 } plane;
 
-struct plane *planes;
+extern struct plane *planes;
 
 struct plane *getplane(const struct region *r);
 struct plane *findplane(int x, int y);
-void	init_planes(void);
-int    getplaneid(const struct region *r);
+void init_planes(void);
+int getplaneid(const struct region *r);
 struct plane * getplanebyid(int id);
 int region_x(const struct region *r, const struct faction *f);
 int region_y(const struct region *r, const struct faction *f);